Process of refrigerating



July 29 1924. 1,503,456

K; L. CURTIS PROCESS OF REFRIGERAT'ING Filed Feb. 28.. 1922 3 Sheets-Sheet l avwam'toz July 29 ,--l924.

K. L. CURTIS PROCESS OF REFRIGERATING Filed Feb. 28, 1922 $51 Gum/mar 4 i a i i i 2 IIIIIIII 3 Sheets-Sheet 2 July 29 1924. 1,503,456

K. L. CURTIS PROCESS OF REFRIGERATING Filed Feb. 28, 1922 3 Sheets-Sheet 5 Patented July 29, 1924.

KENNETH L. CURTIS,

OF YORK, Ni -Y.

PROCESS OF REFRIGERATING.

Appiicatiqn flied iebrnary To all whom it may concern:

Be it known that L-KENN'EifiL. Cti'n'iIs. a citizen of the United States, and resident of New York city, in the countyof New York and State'of New York, have-invented certain new and 'uscful lmprovemcnts in I with the accompanying drawings illustrating s'aid'preferred form of apparatus for Processes of Refrigerating, of which the following is a specification. I i

The invention relates to I an' -'ini'proyed process of refrigerating. Theo'bjec t'of the invention is the provision'of an improved and simplified process for' refrigerating. The invention is particularly useful" for maintaining a refrigerator intended'for'containing foods, etc. at a; suitable temperature. the operation being one in-whicli'a suitable liquid refrigerant, water being preferred. is evaporated from a closed "chamber within the space to be refrigerated. in such a man ner as to constantly maintain' thedesired low temperature in t-he-refrigerat'onf According to the preferred manner of'practicing my prooess,'I automatically maintain a static body of water or other suitable liquid refrigerant in closed refrigerant chamber, and preferably'by meansof a continuously running constant speedpu'mp, I maintain a'partial vacuum over the surface of the water or other refrigerant to produce rapid evaporation so as to cause'refrigcra-' tlOn-Wltllln the refrigerati'ngchamber, but

the rate of evaporation is such, under eonditions such as obtain in practical use-of the dev1ce,- as not to freeze the water or other refrigerating liquid which-constitutesthe ret'rigerant. the evaporation being'con-a ducted m such manner and at such rate as to maintain the temperature of the refrigerant somewhat above its freezing point, and

according to the preferred manner of prac tiring the invention the air in the refrigerator is allowed .to. circulate by-risingand traversing the refrigerant chamber, as by passing through openings therein where the heat is abstracted, the air thereafter again descending.

While this is the preferred manner of 'u'acticing theinvcntion. it is to be understood that the invention is not to be limited to all of these features.

The invention consists in the novel features of the process hereinafter described.

' according to the preferred manner of practic-iug the same. and n connection w th the preferred ap-paratusufor carrying out the 25,1922. sem nasaassr same, and the'inv'ention will be more.particularly pointed out in the appended claims.

Other objects and advantages of the in v'eiition iv'ill more fully appear from the "following description taken in connection carr ing out the process. v order that the invention may be more clcarlyiunderstood attehtion is hereby .directed to the accompanying drawings orming partoffthis application and illustrating one formbf apparatus by which the process may be carried out. In the drawings Fig. 1 represents a somewhat diagrammatio'view, partly in side elevation and partly insection, of the entire apparatus;

' Fig.' '2 is'an enlarged section taken on lines 2-2'of Fig. 1, illustrating the vacuum p mp'ihg apparatus at one point in itsoperatiom" i "j Fig.3 is a sectional View: similar' to that shown in Fig- 2 :illustrati ng the vacuum 1 )ump"1g'apparatus at another point in its operation; @Fig. 4 is Fig. 3'; I

Fig. 5' is a partial enlarged sectional view corresponding to the upper part 'of Fig. 2,

Fig. 6 is a partial enlarged sectional view corresponding to the upper part of Fig. 3. In accordance with-the invention a liquid fed into a chamber which is located in a s ace to be cooled. -I have illustrated a cosed chamber, or. container, 1, located within a refrigerator-P. adapted for containingfood, etc., as in the usual domestic ice box, or refrigerator. The container 1 is preferably located withinv the refrigerator near the upper portion of the interior thereof, and may be supported by suitable'supports3, 3, which are preferably spaced .inwardly somewhahfrom the-outer wallsof a. section taken on-l-ine 4-4 of refrigerating medium, preferably nvater, is .90

the refrigerator. The liquid refrigerating medium, preferably water, as. statec, is fed .into chamber 1 by-a .pipe 4. Means mustbe provided for maintaining the supply of liquid to chamber 1 to compensate .,for

ing'the refrigeratin 1 1 a t eve 1s mam am. ,a

the water or liquid vapors which are withdrawn therefrom dur- I .water is used as the refrigerating medium example at 5, by means of a float valve, the valve 6 being illustrated as pivoted to the wall of container 1 and having an arm 7 carrying a float 8 secured thereto, the valve .6 closing when the li uid reaches the desired level and opening w enthe level falls, in the well known manner.

A suction pump is connected by pipe 9 to the interior of container 1. A partial vacuum is formed in chamber 1 by the opera- ;tion of this pump which causes the refrigerating medium to evaporate and thus to 've up heat, the amount of heat removed ing practically roportional to the amount of vapor remove from chamber 1'. When asis preferred, no provision need be made for condensing and using the same again.

It also may be noted that the thermostat preferably serve as partitions extending from side to side of the refrigerator with openings 11- at the bottom thereof, so that when the device is in operation the warmer air will pass upwardly through the space between partitions 3' and the outerwalls,

I pass downwardly through the pipes or passages 10 where the heat is abstracted, and through 'the holes in shelves 12 and openings 11, the air then again passing up along the outside passages. The refrigerator may be provided with perforated shelves 12 in the usual manner.

The vacuum pumping apparatus is shown as contained within the cylinder 13 and the crank case 14. The vacuum producing or suction apparatus is of improved and novel design, constituting one of the features of the invention,- and is particularly well adapted to produce an exceedingly low vacuum in chamber 1, which is necessary for or highly desirable in the operation of the system.

The yacuum pump which 'is preferably used combines a zero-clearance outlet valve and a mechanically operated inlet valve. The zero-clearance is obtained by making the outlet valve extend over the full diametei' of the cylinder so that the piston may move to. the extreme end of the cylinder or even overtravel without doing any damage.

The inlet valve preferably takes the form of a sleeve which seals the inlet opening by seating at its end in the manner of a pop pet valve and not by sliding over a port to entirely cover or uncover the same, as is customary with sleeve valves. By the use enough pressure on either side of a valve to open the same at any time.

In the preferred form of the apparatus, as illustrated, the vacuum pump apparatus comprises a pair of cylinders 13 and 15 which are secured to an air tight crank case 14, the cylinder 13 being shown as mounted on the upper end of thecrank case, with its lower end opening into the same, while the cylinder 15 is mounted within the lower portionof the crank case. The pistons of the two cylinders are connected to operate in unison, the piston 16 of the upper cylinder serving to draw water vapor, or generally speaking, the vapor of the liquid refrigerant, from chamber 1 in the refrigerator and to dischargethe. contents of the crank case through pipe connection 18 into a suitable receptacle 19, The two cylinders are preferably-the same in their construc-,

tion, except-that the lower is much smaller than the upper one. 1

The exhaust valves 20 and 21 of the cylinders 13 and 15 are preferably both of the full diameters of the cylinders and may be considered as movable cylinder heads.

They are held in place by springs, 22, in the case of the upper cylinder and 23 in the case of the lower cylinder, and are opened, at the end of each outward piston stroke, by the pressure of the exhaust gases or vapor, or condensed liquid in the case of the lower cylinder, during the regular operation of the chamber.

The inlet, valves both preferably take the form of sleeves as shown, the sleeve valve of the upper cylinder 13 being indicated at 24 and the sleeve valve of the lower cylinder being shown at 25. These sleeves surround the pistons and form in effect the cylinder walls. The upper sleeve 24: is preferably provided with an inclined surface 26 at its upper endv which is adapted to seat against a.correspondingl shaped surface 27 on the valve seat 28, w ile the lower sleeve 25. is

provided with a similarly shaped lower end surface 29 which seats against a similar seating surface on the seat 30. The sleeves are preferably moved in one direction by a cam or similar mecharical device and in the other direction by spring action.

In the preferred form of the device, as

illustrated, the two cylinders 13 and 15 are diametrically opposed to each other and the two pistons are operated in unison from the same wrist pin. As illustrated the two pistonsmay be connected together by a rod 31 imaxial alignment with both of the same, a connecting rod 32 being pivotally connected at its upper end to a pin 33 on piston rod 31 while the lower end of the connecting rod in is pivotally connected to the pin 34 on a disc 35 secured to the shaft 36 which is constantly 1 0 rotated} from a suitable motor or power device.

, The together, as by clamping members 37 and 38 secured respectively to the lower end of the uppersleeve and the upper end of the lower sleeve, these clamps being secured toi I gether by rods 39 extending between the same (see Fig. 4). Disc 35 is preferably "formedas a cam oreccentric, a roller 40 2 resting. againstthe outer surface thereof. Preferably roller 40 is carried by an arm 41 having downwardly extending portion 44 above the cam disc 35, arm 41 being pivotally secured'at its outer end, at 42 to the crank case. The cam disc and roller 40 are utilized for moving the sleeve valves in one direction; w.hile springs are used for moving the sleeves in the other direction, suitable springs being indicated at 43 secured at their -and the cylinder 15. r

A'push'rod 45 for actuating the sleeve valves rests'on or is secured to the upper portion of ar'm41. Preferably push rod 45 is formed asa tube, for a. purpose to be explained hereafter, this] tube extending through a suitable opening in the clamping member 37, through an aligned opening in "the top member 46 of the crank case and into an aligned bore or passage 47 formed in cylinder 13, in which it is guided. Preferably push rod operates the sleeve valves throng a spring '48 (see Figs. 2 and 3.) "which must be sufliciently stifi' to move 45 the-sleeves against the pull of springs '43 and-yet be capable of being compressed by a slight overtrav'el of push'rod 45 itself, so

- as to prevent possible damage of ,the parts in case-the push rod tends to overtravel 5'0 slightly for an y reason; Spring 48 may surifrou.nd the rod or tubular member 45 between anal cup or abutment 49 secured to the rod,

at one end, and a cup-50 at the other end w hich bears against ther'clamping member 5:33;)?! ,Accordingly both sleeves-will be moved upwardly by cam 35 and will be moved .j'rlo\vnwardlyl y springs 43 as soon as such .qnpnement is permitted by cam 35 duringto prevent the building up oi a high pres lrjoperation of the-pistons.

. iln the operation of the device as so far 1 1(- ci ;ibed,;,tli e pipeconnection 9 which leads 5 ,1, .to the eyaporating 'chamber 1 in the refrigr ator, iseonnected; through the opening-51 h per. head of cylinder 13 with a whichlcads into the interior of two sleeves 24 and 25 are connected opposite ends to the clamping member 38 cylinder 13, above piston 16, when sleeve 24 is away from its seat 27, as shown in Fig. 6.

In the regular operation of the system,- air and water vapor, or other gases, will be sucked into the space above piston 16 on the descending stroke of the latter, as shown in Figs. 3 and 6,- inlet valve 24 then being opened and outlet valve 20 closed. Valve 24 will be moved upwardly against its seat about the time that piston 16 startson its return or upward movement so that outlet valve 20 will be moved from its seat against the pressure of springs 22 and the contents of the cylinder above the piston will be forced into passage 47 previously referred to. The gases pass from passage 47 into the tubular member 45 which extends into the lower end of the same and pass out through an opening 53 in. member45 into the interior of the air tight crank case.

Piston 17 of the lower cyiinder will be rising on its intake stroke as the upper piston is moving upwardly on its expelling stroke. Condensed water, or air and gases in the crank case, and surplus oil will pass through an opening 54 which extends through cylinder 15. of the lower pump member into an annular space formed in the cylinder 15 surrounding sleeve 25. The sleeve being raised from its seat, as shown in Fig. 2, this material will be drawn into the interior of the cylinder, and when sleeve valve 25 closes and piston 17 descends, the outlet valve 21 will open and this material will be forced out through pipe 118' into the container 19 shown in 1g.

It will be noted that the outlet valves 20 and 21 of the two cylinders extend across the entire diameter of the cylinders and constitute what may be termed zero-clearance outlet valves, since the pistons may travel on their exhaust strokes to the full end of the cylinders, or may even over travel. Valves 20 and 21 may be considered as movable cylinder heads.

The pump pistons are designed to operate at high speed in the system described, and considerable power would he required if the upper piston had to operate at this speed to withdraw air from chamber 1 at the beginning of the operation, when the entire system is filled with air at atmospheric pressure. Also the air thus drawn from the evaporating chamber 1 by the largevupper cylinder and discharged into the crank case would be more than the small lower cylinder could remove in time sure in the crank case, which would further inerease the power required. Accordingly in the preferred form of the invention the lower cylinder alone is utilized at the beginning of the operation, the lower cylinder then withdrawing airfrom the interior of the crank case and through conmotion 47 and a bypass connection 56 from the container 1. ump 'cylinder 15 is considerably smaller in diameter than the upper pump cylinder and very little power is required to operate the same even with the entire apparatus full of air. Automatic means are provided, in the preferred form of invention to become effective, when a suf ficient vacuum has-been established inthe system, to cut in the upper cylinder so that from this time on the larger capacity upper cylinderwill be effectite for maintaining vacuum and evaporating the water gases from chamber 1, the lower chamber serving from this time on merely to remove the air or gas, oil and condensed liquid from the crank case. a

In the form of construction described'bypass 56 extends from the inlet opening 51 through a valve o'penin 56, 57, into, the space 58 at the upper en of the cylinder in which the outlet valve 20 is seated, this space 58 opening into the passage 47 which leads to the crank case. A valve 59 is positioned to seal the opening 56 -extendlng from the horizontal portion of bypass 56 into the recess 57, when a suilicient vacuum has been established in the system, so as to shut off the bypass.

This valve 59 rests on a pile of air tight containers 60 (Figs. 5 and (3) which rest on a support 61 which extends across the construction within space 58. Containers 6O are thin hollow members, of what may be termed pill box construction, preferably formed of very thin metal. They are filled with air at atmospheric pressure, and will lie flat on each other on support 61 when the pressure surroundin them in space 58 and bypass 56 is atmospheric, in which case an opening will be provided over and.

around the containers, as is shown in Fig. 5. When this condition exists the lower pump cylinder will draw directly through passage -17 and bypass 56, from chamber 1, and the upper pump cylinder will be inoperative. After the lower pump has operated sufiiciently to reduce the pressure in the crank case, containers 60 will expand because of the unbalanced pressure of the air confined inside the same, and valve 59 will be lifted and held against its seat at the top of space 57, as is shown in Fig. 6, whereby the bypass 56 will be closed and the upper pump cylinder rendered effective.

Inthe preferred construction of'appara- .tus the wrist pin 33 is preferably mounted between ball bearings 62 and the crank pin is similarly provided with ball bearings (not shown). The crank shaft 36 is preferably providedwith a step bearing 63 to take the thrust caused by the vacuum in the crank case, the step' bearing formin a seal and preventing air from leaking into the oil is sucked upwardly into the up crank-case at this point. Oil may be supplied to the face of this step b'earimi, through pipe 64:, the oil being slowly sucked into the crank case along the surface of the crank shaf 36 and thereby lubricating the crank shaft.

' The remaining parts of the pumping apparatus are preferably lubricated by a single oil supply pipe65, indicated in Figs. 1 and 4, which supplies oil to an annular recess 66 located between "theupper cylinder sleeve 24 and the cylinder casing 13 This s ace 58 surrounding sleeve 24 whenca it c-ws over the upper edge of sleeve '34, when open, into the cylinder above the piston. Oil is also sucked down from recess 66 intc the crank case, where it is splashed by the crank disc 35 so as to reach every moving part in the crank case.

The receptacle 19 into which the lower cylinder 15 discharges serves as an oil reservoir and also as a separator to recover the surplus oil from the discharge of the pump. The condensed water vapor from'the crank case, when water is the refri rating fluid used, settles to the bottom 0 vessel 19, as is indicated at 66, the oil rising above the water, as is indicated at 67. The oil is drawn upwardly from this s cc by pipe 65, previously referred to, an is used own again. The water is forced upwardly in a trap 68, by the weight of the oil 67 show the same in vessel 19, the water flowing out through a ipe 69 in trap 68. Y

The refrigerating apparatus described i: inherently self regulating, because as th temperature of the water chamber 1 is low ered, the water vapor withdrawn therefrom through pipe 9 becomes less dense-and a: the amount of cooling produced inchambei 1 at a given pumping speed is directly pro portional to the amount of va or removed it is directly proportional to t e density or the vapor. For exam 1 at 40 degrees F temperature one poun f steam occupie 2438 cubic feet, and at 32 degrees'F. i occupies 3294 cubic feet. The removal 0: one pound of steam will produce practical]; the same amount of cooling at either tem perature.

When a eater cooling efl'eot is requirei in the refrigerator, that is for example when food products are placed in the refrig erator which require coolinfii the tem a ture of water chamber 1 w' rise, an th vapor removed will have a greater density The suction pum runs at constants ee and in removing t e vapor ofgreater e s1 Jty it removes more heat, which is the con dition desired. Ina like manner when th temperature of the chamber 1 falls less has will be removed therefrom because of th vapor removed being of lesser density. A stated, the refrigerant will not drop below refrigerator will accordingly be maintained within a narrow range, this range being not sufliciently great to interfere with the satisfaotory operation of the apparatus. As the pump runs continuously no automatic devices for starting and stopping the driving motor are necessary. Those features of my invention which are herein described and not claimed, such as the pump per se and the refrigerating system or apparatus as a whole, are claimed respectively in my conding applications Serial No. 582.128, led August 16, 1922, and Serial No. 581,304, filed A st 12, 1922. y

. It is lieved that the method of practicing the process, and also the operation f the-ap ratus described, will be apparent from t e above description. While I have described the preferred manner of practicing the process in connection with the preferred form of apparatus for carrying out the same, it will be understood by those skilled in the art, after understanding the invention, [nat- \Zll'lOllS changes and modifications may be made therein without departr ing from the spirit or scope of the invention, and I do not wish to be understood as limiting myself other than as indicated in the appended claim.

What I claim is Process of refrigerating under regulation by'an inherent property of the saturated vapor of the refrigerant ,to automatically maintain a suitable refrigerating temperature. which comprises, maintaining a body of water at a constant level in aclosed space which is to be maintained .at a refrigcrating temperature above 32 Faln, evaporating the water in said space and removing the vapor by suction, the suction means operating continuously and at a constant speed to remove water vapor at a constant rate volumetrically, the suction means operating at such rate and being so proportioned that it will not freeze the refrigerant. under ordinary low temperatures to which household refrigerators are subjected, and will maintain, with the varying density of the vapor, the temperature of said body of water, at approximately the desired point above 32 Fab.

Signed at New York city, in the county of New York and State of New York this 21st day of February D. 1922.

KENNETH L. CURTIS. 

